The present invention relates to vehicle lighting accessories, and in particular to a vehicle interior light including a lens for uniformly distributing light to illuminate a specific area in a uniform manner.
Modern vehicles include a variety of lighting accessories, such as map lights, overhead consoles including lights, and other passenger compartment lights. The lighting accessories must provide enough light at a sufficient intensity and uniformity over a large enough area to illuminate the particular area to be viewed or to provide light for the particular task to be performed. Such lighting should not provide stray light that will distract the attention of the driver of the vehicle. Various lighting accessory configurations have been used with varying degrees of success, however, further improvements are desired to provide better control over the size and uniformity of the resultant light distribution, along with a reduction in stray light and glare.
One technology in particular, i.e. "pillow optics" technology, has been used in lens of map lights in an effort to improve on the above noted problems. Pillow optics technology uses a plurality of small, dish-shaped depressions or protrusions on a lens surface to direct individual sections of light in desired directions. In effect, each dish-shaped depression or protrusion acts like a mini magnifying glass to direct the light in a given direction. The size of these depressions or protrusions, their radii, and their relative orientation is predetermined through relatively extensive testing to achieve an acceptable pattern of light. The individual depressions can be substantially any size desired, but usually are in the range of about 1 mm.times.1 mm to about 2 mm.times.3 min. However, "pillow optics" lens characteristically produce non-uniform light patterns. For example, "pillow optic" lens result in glare, which is blinding, dazzling spots of light; "spider webbing," which is randomly oriented fine streaks of bright light having the appearance of a spider web; light/dark patchiness, which is relatively bright regions and adjacent relatively dark regions within the overall pattern; and chromatic aberrations, which are rainbow-like colored patterns at the edges of the lighted pattern.
With pillow optics technology, it is possible to redesign individual sections of the "pillow optics" lens to redistribute light from bright areas toward dark areas. However, it is not possible to control light rays well enough with the pillow optics technology to eliminate these problems. Such non-uniform light patterns are irritating to the human eye and make it difficult to use the light for very long or for tasks such as for reading or studying a map. Further, it is not uncommon to spend over 150 hours of design, testing, and redesign time to arrive at an acceptable light pattern before prototypes can be made. In the highly competitive automotive industry, such extensive testing and design time adds excessive cost to a product and can delay the introduction of new products. Also, a lens including pillow optics technology has a multi-surfaced crystal-like appearance that frequently does not compliment the non-glossy decor of other components in the vehicle passenger compartment, thus creating a less than desirable mismatched appearance. Nonetheless, "pillow optics" technology has been generally accepted by the industry as one of the preferred ways of controlling/dispersing light into a predetermined pattern.
Modern luxury vehicles are also often provided with lighting accessories having lenses incorporating "prism optics" technology, sometimes called "V-groove optics" technology, to control light distribution. Prism optics technology uses a plurality of elongated triangularly-shaped prismatic surfaces to direct individual sections of light in desired directions. However, prism optics lens have the same problems as pillow optics lens, as noted above, such as glare, "spider webbing," light/dark patchiness and chromatic aberrations. Also, in addition to the problems noted above, both of these lenses must be spaced significantly from the light source in order to be very effective. This results in a relatively thicker product, which is undesirable since passenger headroom is a problem in vehicle passenger compartments, especially in view of governmental standards relating to occupant safety such as for crash testing.
Therefore, a vehicle accessory light including a lens for uniformly illuminating an area solving the aforementioned problems is desired.